Empresa Brasileira de Pesquisa AgropecuáriaEmbrapa Hortaliças

Ministério da Agricultura, Pecuária e Abastecimento

Mudanças Climáticas Globais e a

Produção de Hortaliças

Ítalo Moraes Rocha GuedesEditor Técnico

Brasilia, DF

2009

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Embrapa HortaliçasBR 060, Rodovia Brasília-Anápolis, Km 09Caixa Postal 218, 70359-970, Brasilia, DFFone: (61) 3385-9009Fax: (61) 3556-5744sac@cnph.embrapa.brwww.cnph.embrapa.br

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1a edição1a impressão (2009): 500 exemplares

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Dados Internacionais de Catalogação na Publicação (CIP)Embrapa Hortaliças

Guedes, Italo Moraes Rocha

Mudanças climáticas globais e a produção de hortaliças I [taloMoraes Rocha Guedes, editor técnico. - Brasflia : Embrapa Hortaliças,2009.

132 p.

ISBN 978-85-86413-17-9

1. Hortaliça - Produção - Clima. I. Título.

CDD 635.0469©Embrapa, 2009

Comissão Organizadora do Evento:Carla Timm

Celso Luiz Moretti .

Jairo Vidal Vieira

WarleyMarcos Nascimento

Coordenador:Ítalo Moraes Rocha Guedes

Realização:Embrapa Hortaliças

Patrocinadora do Workshop "Efeitos das MudançasClimáticas na Produção de Hortaliças",realizado em 20 de novembro de 2009:

Fundação de Apoio à Pesquisa do Distrito Federal- FAPDF

LOPES, C. A.; AVILA, A. C. Doenças do tomateiro. Brasilia, DF: EmbrapsHortaliças, 2005. 151 p.

MINAM!, K.; HAAG, H. P. O tomateiro. Piracicaba: Fundação Cargil, 2005. 397 P.

REIS, A.; DIAS, R. c,ARAGÃO, F.A. S.; BOITEUX, L. S. Caracterização do perfilpatogênico de isolados de Podosphaera xanthii em cucurbitáceas na região nordeste doBrasil. Horticultura Brasileira, Brasilia, DF, v. 23, p. 362, 2005. Suplemento.

VALE, F. X. R.; ZAMBOLIM, L.; PAUL, P. A.; COSTA, H. Doenças causadas porfungos em tomate. In: ZAMBOLIM, L.; VALE, F. X. R.; COSTA, H. Controle dedoenças de plantas hortaliças. Viçosa, MG: Universidade Federal de Viçosa, 2000.v. 2, p. 699-756.

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CAPÍTULO V

Potential impacts of climate changes on thequality of fruits and vegetables

C. L. Moretti', L. M. Mattos', A.G. Calbo", S.A. Sargenr'I Embrapa Vegetables, 2 Embrapa Agricultural Instrumentation, 3 Horticultural Sciences

Department, University of Florida, Gainesville

Introduction

Climate on Earth has changed many times during the existence ofour planet, ranging from the ice ages to periods of warmth. During the lastseveral decades increases in average air temperatures have been reported andassociated effects on climate have· been debated worldwide in a variety offorums. Due to its importance around the globe, agriculture was one of thefirst sectors to be studied in terms of potencial impacts of climate change(ADAMS et al., 1990). Many alternacives have been proposed to growersaimed at minimizing losses in yield. However, few studies have addressedchanges in postharvest quality of fruits and vegetable crops associated withthese alterations, Nowadays, climate changes, their causes and consequences,gained importance in many other areas of interest for sustainable life onEarth. The subject is, however, controversial.

According to studies carried out by the Intergovernrnental Panel onClimate Change (Ipcq, average air temperatures will increase between 1.4and 5.80 C by the end of this century, based upon modeling techniques thatincorporated data from ocean and atmospheric behavior (IPCC, 2001). Thepossible impacts of this study, however, are uncertain since processes suchas heat, carbon, and radiation exchange among different ecosystems arestill under invescigation. Less drastic estimates predict temperature increaserates of 0.0880 C per decade for this century (KALNAY; CAI, 2003). Other,investigators forecast for the near future that rising air temperature couldinduce more frequent occurrence of extreme drought, fiooding or heat wavesthan in the past (ASSAD et al., 2004).

Higher temperatures can increase the capacity of air to absorbwater vapor and, consequently, generate a higher demand for water, Higher

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evapotranspiration indices could lower or deplete the water reservoir in soils,creating water stress in plants during dry seasons. For example, water stress isof great concern in fruit production, because trees are not irrigated in man:--production areas around the world. It is well documented that water stressnot only reduces crop productivity but also tends to accelerate fruit ripening(HENSON,2008).

Exposure to elevated temperatures can causemorphological, anatornical,physiological, and, ultimately, biochemical changes in plant tissues and, as aconsequence, can affect growth and development of different plant organs.These events can cause drastic reductions in commercial yield. However, bvunderstanding plant tissues physiological responses to high temperatures,mechanisms of heat tolerances and possible strategies to improve yield, it ispossible to predict reactions that will take place in the different steps of fruirand vegetable crops production, harvest and postharvest (KAYS, 1997).

Besides increase in temperature and its associated effects, climatechanges are also a consequence of alterations in the composition of gaseousconstituents in the atrnosphere. Carbon dioxide (CO) and ozone (OJconcentrations in the atrnosphere are changing during the last decade and areaffecting many aspects of fruit and vegetable crops production around theglobe (FELZER et al., 2008).

Carbon dioxide concentrations are increasing in the atrnosphereduring the last decades (MEARNS, 2000). The current atrnospheric CO2

concentration is higher than at any time in the past 420,000 years (pETITet al., 1999). Further increases due to anthropogenic activities have beenpredicted. Carbon dioxide concentrations are expected to be 100% higherin 2100 than the one observed at the pre-industrial era (IPCC, 2007). Ozoneconcentration in the atrnosphere is also increasing. Even low levels of ozonein the vicinities of big cities can cause visible injuries to plant tissues as wellas physiological alterations (FELZER et al., 2007).

The above mentioned climate changes can potentialiy cause postharvestquality alterations in fruit and vegetable crops. Although many researchershave addressed climate changes in the past and, in some cases, focusedpostharvest alterations, the inforrnation is not organized and available forpostharvest physiologists and food scientists that are interested in betterunderstanding how these changes will affect their area of expertise.

In the present article we review how changes in ambient temperatureand levels of carbon dioxide and ozone can potentialiy impact the postharvestquality of fruit and vegetable crops.

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Harvest and postharvest

Harvest of fruit and vegetable crops occurs in different times of the:ocardepending on cultivar, water regime, climate conditions, pest control,cultural practices, exposure to direct sunlight, temperature management andrnarurity index, among other important pre-harvest factors.

After crops are harvested, respiration is the major pracess to becontrolled. Postharvest physiologists and food scientists do not have manyoptions to interfere with the respiratory process of harvested cornrnodities,since they are largely dependent on the product speciíic characteristics,S}..LTVEIT,2002).

In arder to minimize undesirable changes in quality parameters duringthe postharvest period, growers and entrepreneurs can adopt a series oftechniques to extend the shelf life of perishable plant products. Postharvestrechnology comprises different methods of harvesting, packaging, rapidcaoling, storage under refrigeration as well as modified (MA) and controlled(CA) atrnospheres and transportation under controlled conditions, amongother important technologies. This set of strategies is of paramountimportance to help growers ali over the world to withstand the chaliengesthat climate changes will impose throughout the next decades.

Effects of temperature

Fruit and vegetable growth and development are influenced by differentenvironrnental factors (BINDI et al., 2001). During their development, hightemperatutes can affect photosynthesis, respiration, aqueous relations andmembrane stability as well as levels of plant hormones, and primary andsecondary metabolites (BEWLEY, 1997).

Most of the physiological processes go on normaliy in temperaturesranging fram 0° C to 40° C. However, cardinal temperatures for thedevelopment of fruit and vegetable crops are much narrower and, dependingon the species and ecological origin, it can be pushed towards 0° C fortemperate species from cold regions, such as carrots and lettuce. On the otherhand, they can reach 40° C in species from tropical regions, such as mapycucurbits and cactus species (WENT, 1953).

A general temperature effect in plants involves the ratio betweenphotosynthesis and respiration (WENT, 1953). High temperatures canincrease the rate of biochemical reactions catalyzed by different enzymes.However, above a certain temperature threshold,· many enzymes lose their

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function, potentially changing plant tissue tolerance to heat stresses (EIETO;TALON,1996).

Temperature is of paramount importance in the establishment of aharvest index. The higher the temperature during the growing season, thesooner the crop-will mature. Hall et alo(1996) and Wurr et alo(1996) reportedthat lettuce, celery, cauliflower and kiwi grown under higher temperaturesmatured earlier that the same crops grown under lower tempetatures.

Rapid coolingFruit and vegetable crops are generally cooled after harvest and before

packing operations. Cooling techniques have been used since the 1920'sto remove field heat from fresh produce, based on the principle that shelflife is extended 2- to 3-fold for each 10°C decrease in pulp temperature.Rapid cooling optimizes this process by cooling the product to the lowestsafe storage temperature within hours of harvest, By reducing the respirationrate and enzyme activity; produce quality is extended as evidenced by slowerripening/ senescence, maintenance of firmness, inhibition of pathogenicrnicrobial growth and rninimal water loss (rALBOT; CHAU, 2002).

Rapid cooling methods such as forced-air cooling, hydrocooling andvacuum cooling demand considerable amounts of energy (rHOMPSON,2002). Therefore, it is anticipated that under warmer climatic conditions, fruitand vegetable crops will be harvested with higher pulp temperatures, whichwill demand more energy for proper cooling and raise product prices.

Fruit RipeningHigh temperatures on fruit surface caused by prolonged exposure

to sunlight hasten ripening and other associated events. Ripening of 'Hass'avocados was also affected by exposure to high temperatures during growthand development (WOOLF et al., 1999).

Tomate ripening occurred normally in terms of color development,eth.yleneevolution, and respiratory climacteric after three days at temperaturesabove 36°C. However, ripening was slower than freshly harvested fruit(LURIE; KLEIN, 1991).

The immediate effects of heat treatrnents have generally been toinhibit respiration and ethylene production, reduce protein synthesis, andincrease protein breakdown (EAKS, 1978; LURIE; KLEIN, 1990, 1991;FERGUSON et al., 1994).

Eaks (1978) determined the respiratory rate of mature 'Hass' avocadofruits at 20 to 40°C. Typical climacteric patterns occurred at 20, 25, 30 and

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35° C with the climacteric maximum increasing with temperature, but only adecreasing respiratory rate with time was observed at 40° C. The exposure toexogenous ethylene or propylene hastened the ripening response up to 35° C.However, at 40° C the respiratory rate was increased, but ethylene productionand normal ripening did not occur.

Although there are few reports in the literature on other specific effectsof exposure to high temperatures during the growing season and subsequentchanges in ripening behavior, extrapolations can be made from reports onpostharvest ripening (WOOLF; FERGUSON, 2000). High temperatures onfruit surface caused by pronounced exposure to sunl.ight can hasten ripeningand other associated events. The above studies suggest that changes in ripeningbehavior are likely to occur when fruit and vegetable crops are exposed tohigher temperatures prior to harvest. Chan et alo(1981); Picton and Grierson(1988) observed that high temperature stresses inhibited ethylene productionand cell wall softening in papaya and tomato fruits. On the-other hand..cúcurnber fruits showed increased tolerance to high temperature stress (32.50C) with no change in in oitroACC oxidase activity (CHAN; LINSE, 1989).

Quali!J parameters _Extensive work has been carried out for more than three decades

focusing quality properties of fruit and vegetable crops exposed to highternperatures during growth and development. Flavor is affected by hightemperatures. Apple fruits exposed to direct sunlight had a higher sugarcontent compared to those fruits grown on shaded sides (EROO KS; FISHER,1926). Grapes also had higher sugar content and lower levels of tartaric acidwhen grown under high temperatures (KLIEWER; LIDER, 1968~1970).

Dry matter content is used as a harvest indicator for avocados dueto its direct correlation with oil content, a key quality component (LEE etal., 1983). For example, the Stateof California produces about 80% of theavocados grown in the USA (Mexican and Guatemalan strains and theirhybrids) and requires a rninimum oil content from 19% to 25% dependingupon the cultivar (KADER; ARPAIA, 2002). Avocados with higher drymatter content take longer to ripen which could pose a serious problem for I

growers planning to market their fruits immediately after harvest (WOOLF etal., 1999,2000). Thus, fruit and vegetable growers, packers and shippers mustpay dose attention to arnbient temperatures during growth and developmentas well as maturity indices to assure harvest at the appropriate time.

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Antioxidant activityAntioxidants in fruit and vegetable crops can also be altered by

exposure to high temperatures during the growing season. Wang and Zheng(2001) observed that 'Kent' strawberries grown in warmer nights (18 to 22°C) and warmer days (25° C) had a higher antioxidant activity than berriesgrown under cooler (12° C) days. The investigators also observed that hightemperature conditions significantly increased the levels of flavonoids and,consequently, antioxidant capacity McKeon et alo (2006) also addressed theeffects of élimate changes in functional components. They verified that highertemperatures tended to reduce vitarnin content in fruit and vegetable crops.

Pbysiologica! disorders and tolerance to high temperaturesExposure of fruit and vegetable crops to high temperatures can

result in physiological disorders and other associated internal and externalsymptoms.

Exposure of tomato fruits to temperatures above 30° C suppressesmany of the parameters of normal fruit ripening induding color development,softening, .respiration rate and ethylene production (BUESCHER, 1979;HICKS et al., 1983). It is also weli known that exposure of fruit to temperature. extremes approaching 40° C can induce metabolic disorders and facilitatefungal and bacterial invasion,

In general, visible evidence of heat injury on toma toes appears asyellowish-white patches on the side of fruits (MOHAMMED et al., 1996).Electrolyte leakage in harvested 'Dorado tomatoes exposed to directsunlight (34 ± 2° C) for 5 h was 73% higher than fruits held in shaded (29 ±2° C) conditions. Although no significant changes in firmness were observedfor either treatments foliowing storage at 20° C for 18 days, the percentageof infected fruits was 35% higher in fruits exposed to direct sunlight(MOHAMMED et al., 1996).

Frequent exposure of apple fruit to high temperatures, such as 40°C, can result in sunburn, development of watercore and loss of texture(FERGUSONet al., 1999). Moreover, exposure to high ternperarures on thetree, notably dose to or at harvest, may induce tolerance to low temperaturesin postharvest storage. Avocado fruit grown in New Zealand and exposedto direct sunlight had pulp temperatures at harvest that frequently exceeded35° C (W00LF et al., 1999). During subsequent storage at O °C (below therecommended temperature), these fruit had lower incidences of chillinginjury than fruit harvested from shaded parts of the tree.

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Practical effects of climate change have already been experienced insome parts of the globe. For example, increased temperatures in Sambalpur,India, have delayed the onset of winter. As a consequence, caulifíower yieldshave dropped significantly (pani, 2008). Where growers commonly harvested1-kg heads, inflorescences are now smaller, weighing 0.25 - 0.30 kg each.Reductions in yield drive up production costs, an effect also observed fortomate, radish and other native Indian vegetable crops. In Brazil, the BrazilianAgricultural Research Corporation (Embrapa) has estimated a 50% reductionin soybean yield in the center-west region ("cerrado'') by 2020, assuming anaverage increase of 0.3 and 0.5° C per year (unpublished data).

Effects of carbon dioxide exposure

The Earth's atmosphere consists basically of nitrogen (78.1%) andoxygen (20.9%), with argon (0.93%) and carbon dioxide (0.031 %) comprisingnext most abundant gases (LIDE, 2009). Nitrogen and axygen are notconsidered to playa significant role in global warming because both gases arevirtually transparent to terrestrial radiation. The greenhouse effect is primarilya combination of the effects of water vapor, CO2 and minute amounts ofother gases (methane, nitrous oxide, and ozone) that absorb the radiationleavirig the Earths surface (IPCC, 2001). The warming effect is explainedby the fact that CO

2and other gases absorb the Earth's infrared radiation,

trapping heat. Since a significant part of ali the energy emanated from Earthoccurs in the form of infrared radiation, increased CO2 concentrations meanthat more energy will be retained in the atmosphere, contributing to globalwarming (L0YD; FARQUHAR, 2008). Carbon dioxide concentrations in theatmosphere have increased approximately 35% from pre-industrial·times to

2005 (IPCC, 2007).Besides industrial activities, agriculture also contributes to the emission

of greenhouse gases. In 2007 the agricultural sector in the United States wasresponsible for the emission of 413.1 teragrams of CO2 equivalents (Tg CO2

Eq.), or 6% of the total production of greenhouse gas emissions. Methaneand nitrous oxide were the primary sources emitted by USA agricultural

activities (EPA,2009).

Growth and pf!ysiological alterationsMany papers published during the last decade have dearly associated

global warming with the increase in carbon dioxide concentration in theatmosphere. Changes in CO

2concentration in the atmosphere can alter plant

71

tissues in terms of growth and physiological behavior. Many of these effectshave been studied in detail for some vegetable crops (CURE; ACOCK, 1986;BAZZAZ, 1990; IDSO; IDSO, 1994). These studies concluded, in summary,that increased atmospheric CO2 enhances net photosynthesis, biomassproduction, seed yield, light, water, and nutrient use efficiency and plant waterpotential.

As noted previously in the present review, this theme remainscontroversial. Clark (2004), working on tropical forests, argued that increasingatmospheric CO2 has no or little result in biomass production rates. In otherwords, she stressed the growth of tropical forests is not carbon limited and,additionally, that since higher temperatures increase respiration and othermetabolic processes, that increased atmospheric CO2 can reduce forestproductivity.

Qualiry parametersHõgy and Pangmeier (2009) studied the effects of high CO

2

concentrations on the physical and chemical quality of potato tubers. Theyobserved that increases in atmospheric CO2 (50% higher) increased tubermalformation in approximately 63%, resulting in poor processing quality, anda trend towards lower tuber greening (around 12%).

Higher (550 umol CO2 / mol) concentrations of CO2 increased glucose(22%), fructose (21%) and reducing sugars (23%) concentrations, reducingtubers quality due to increased browning and acryl amide formation in Prenchfries. They also observed that proteins, potassium and calcium levels werereduced in tubers exposed to high CO2 concentrations, indicating loss ofnutritional and sensory quality.

Bindi, Fibbi and Miglietta (2001) studied the effects of high atmosphericCO

2during growth on the quality of wines. These authors observed that

elevated atmospheric CO2levels had a significant effect on fruit dry weight,

with increases ranging from 40 to 45% in the 550 mmol CO2

/ mol treatmentand from 45 to 50% in the 700 mmol CO

2/ mol treatment, Tartaric acid

and total sugars contents increased around 8 and 14%, respectively, by risingC0

21evels up to a maximum increase in the middle of the ripening season.

However, as the grapes reached the maturity stage, the CO2 effect on bothquality parameters almost completely disappeared.

Overall wine quality was not significantly affected by elevated CO2•

Purthermore, no significant differences were detectable among plants grownin the two enriched treattnents, and the effects of elevated CO2 concentration

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were similar in the two growing seasons. lhe researchers concluded thatthe expected rise in CO2 concentrations may strongly stimulate grapevineproduction without causing negative repercussions on quality of grapes andwine.

Effects of ozone exposure

Formation and distributionOzone in the troposphere is the result of a series of photochemical

reactions involving carbon monoxide (CO), methane (CHJ andother hydrocarbons in the presence of nitrogen species (NO + NO)(SCHLSINGER, 1991). It forms during periods of high temperature andsolar irradiation, normally during summer seasons (MAUZERALL; WANG,2001). It is also formed, naturally during other seasons, reaching the peakof natural production in the spring (SINGH et al., 1978). However, higherconcentrations of atmospheric ozone were found during summer due toincrease in nitrogen species and emission of volatile organic compounds(MAUZERALL; WANG, 2001).

Visible i1!fury and pbysiologica! effectsThe effects of ozone on vegetation have been studied both under

laboratory and field experiments. Stomatal conductance and ambientconcentrations are the most important factors associated with ozone uptakeby plants. Ozone enters plant tissues through the stomates, causing directcellular damage, especially in the palisade cells (MAUZERALL; WANG,2001). The damage is probably due to changes in membrane permeabilityand may or may not result in visible injury, reduced growth and, ultimately,reduced yield (KRUPA; MANNING, 1988).

Visible injury symptoms of exposure to low ozone concentrationsinclude changes in pigmentation, also known as bronzing,leaf chlorosis, andpremature senescence (FELZER et al., 2007). Since leafy vegetable crops areoften grown in the vicinity of large metropolitan areas, it can be expectedthat increasing concentrations of ozone will result in increased yellowing of ileaves. Leaf tissue stressed in this manner could affect the photosyntheticrate, production of biomass and, ultimately, postharvest quality in terms ofoverall appearance, color and flavor compounds.

Using modeling tools, Fuhrer et alo (1997) concluded that ozoneconcentrations higher than 40 nmol 03 / mol can result in a 10% yield

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reduction in clifferent tree species in Southern Europe. In open field stuclies a2-fold increase in e02 concentration caused a 15% increase in soybean yield,whereas a 20% increase in the atmospheric ozone offset the yield increasingeffect of e02 (HENSON, 2008).

Grulke and Miller (1994) and Tjoelker, Volin, Oleksyn and Reich(1995) observed that higher ozone concentrations can affect both thephotosynthetic and respiratory processes. They verified that branches withinthe upper canopy of sugar maple (Acer saceharumMarsh.) submitted to ozoneconcentrations of 95 nmol 03 / rnol (twice-ambient concentrations) showedreduced light-saturated rates of net photosynthesis by 56% and increased darkrespiration by 40%. These researchers also observed that ozone reduced netphotosynthesis and impaired stomatal function, with these effects dependingon the irracliance environment of the canopy leaves.

The present review ofthe pertinent literature related to plant responsesto ozone exposure reveals that there is considerable variation in speciesresponse. Greatest impacts in fruit and vegetable crops may occur fromchanges in carbon transporto Underground storage organs (e.g., roots, tubers,bulbs) normally accumulate carbon in the form of -starch andsugars, both ofwhich are important quality parameters for both fresh and processed crops.If carbon transport to these structures is restricted, there is great potentialto lower quality in such important crops as potatoes, sweet potatoes, carrots,onions and garlic.

Exposure of other crops to elevated concentrations of atrnosphericozone can induce external and internal clisorders, which can occursimultaneously or independently. These physiological clisorders can lower thepostharvest quality of frmt and vegetable crops destined for both fresh marketand processing by causing such symptoms as yellowing (chlorosis) in leafyvegetables, alterations in starch and sugars contents fruits and in undergroundorgans. Decreased biomass production directly affects the size, appearanceand other important visual quality parameters. Furthermore, impair stomatalconductance due to ozone exposure can reduce root growth, affecting cropssuch as carrots, sweet potatoes and beet roots (FELZER et al., 2007).

Quality parametersSkog and Chu (2001) carried out a set of experiments to determine

the effectiveness of ozone in preventing ethylene-mecliated deteriorationand postharvest decay in both ethylene-sensitive and ethylene-producing

74

commoclities, when stored at optimal and sub-optimal temperatures. Onmushrooms, which have no known site of ethylene activity (ABELES, 1984),effects from ozone would be antimicrobial only. Ozone at the concentrationof 0.04 ul, / L appeared to have potential for extending the storage life ofbroccoli and seedless cucumbers, both stored at 3 "C,When mushrooms werestored at 4° e and cucumbers at 10 "C, response to ozone was minimal.

Quality attributes and sensory characteristics were evaluated ontomato fruits cv. Carousel after ozone exposure (concentration ranging from0.005 to 1.0 flmol / mol) at 13° e and 95% RH. Soluble sugars (glucose,fructose), fruit firmness, weight loss, antioxidant status, e0

2/ H

20 exchange,

ethylene production, citric acid, vitamin e (pulp and seed) and total phenoliccontent were not significantly affected by ozone treatment when comparedto fruits kept under ozone-free air. Sensory evaluation revealed a significantpreference for fruits subjected to low-level ozone-enrichment (0.15 flmol /mol) (TZORTZAKlSA et al., 2007).

The quality of persimmon (Diospyros kaki L. F.) fruits (cv Fuyu)harvested at two clifferent harvest dates was evaluated after ozone exposure.Fruits were exposed to 0.15 flmol / moI (vol/vol) of ozone for 30 days at15° e and 90% relative humiclity (RH). Astringency removal treatrnent (24h at 20° e, 98% eOJ was performed and fruits were then stored for 7 daysat 20° C (90% RH), imitating commercial conditions, Flesh softening wasthe most important clisorder that appeared when fruit were transferred from15 "C to commercial conclitions. Ozone exposure was capable to maintainfirmness of second harvested fruits, which were naturally softer that firstharvested fruits, over commercial limits even after 30 days at 15° e plusshelf-life. Ozone-treated fruit showed the highest values of weight loss andmaximum electrolyte leakage. However, ozone exposure had no significanteffect on color, ethanol, soluble solids and pH. Furthermore, ozone-treatedfruits showed no signs of phytotoxic injuries (SALVADOR et al., 2006).

Conclusions,<

Understanding how climate changes will impact mankind in thedecades to come is of paramount importance for our survival. Temperature,carbon dioxide and ozone directly and indirectly affect the production andquality of fruit and vegetable crops grown in clifferent climates around theworld. Temperature variation can directly affect crop photosynthesis, and arise in global temperatures can be expected to have significant impact on

75

postharvest quality by altering important quality parameters such as synthesisof sugars, organic acids, antioxidant compounds and firmness.

Rising levels of carbon clioxide also contribute to global warming, byentrapping heat in the atrnosphere. Prolonged exposure to CO 2 concentrationscould induce higher incidences of tuber malformation and increased levelsof sugars in potato and climinished protein and mineral contents, leaclingto loss of nutritional and sensory quality. Increased levels of ozone in theatrnosphere can lead to detrimental effects on postharvest quality of fruirand vegetable crops. Elevated levels of ozone can induce visual injury andphysiological clisorders in clifferent species, as well as significant changes indry matter, reducing sugars, citric and malic acid, among other importamquality parameters.

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